The field of this invention is intervertebral implant instrumentation and methods of implantation.
A variety of different intervertebral implants and distraction tools have been designed, used and patented. Intervertebral implants are used to replace diseased or damaged vertebral discs. Some implant designs are hollow to allow for the insertion of bone graft material that can fuse adjoining vertebrae. Some implant designs are nearly square in shape. The square shape typically tends to prevent the easy insertion of the implant into the intervertebral space. Many of the existing implant designs require complex and potentially dangerous pre-drilling and tapping of the intervertebral space prior to inserting the implant.
Some implants include vertical ridges at the surfaces that contact the vertebral laminar surface. Simple vertical ridges typically do not prevent retropulsion of the implant relative to the intervertebral space. Furthermore, vertical ridges can prevent easy insertion of the implant.
In some instances, the surgical implant can become unstable after the surgical insertion. The implant can be subject to torsional forces that can jeopardize the integrity of the procedure.
A distraction tool is used for preparing an intervertebral space prior to insertion of an implant. Some of the existing distraction tools include a tapered proximal end and some include square corners about the cross section. The square cross section provides a stable footing once the distractor is inserted. Other distraction tools include rounded corners about the cross section. Such a configuration allows for easy insertion of the distractor.